Question

At -40°C, a sample of gas has a volume of 233 mL. On heating, the volume expands to 313 mL. Assuming constant pressure, what is the new Celsius temperature?

Answer 1

The new temperature in degrees Celsius is 40 degrees C.

Explanation:

This isthe an example of Charles' law which states the volume of a gas that is held at a constant pressure varies directly with the Kelvin temperature. The formula used to solve this problem is `V_1/T_1=V_2/T_2`.

Given/Known
`V_1="233 mL"`
`T_1=-40^"o""C"+273.15="233 K"`
`V_2="313 mL"`

Unknown
`T_2` in degrees C

Solution
Rearrange the equation to isolate `T_2` and solve.

`V_1/T_1=V_2/T_2`

`T_2=(V_2T_1)/V_1`

`T_2=(313cancel"mL"xx233"K")/(233cancel"mL")="313 K"`

Convert temperature in Kelvins to degrees Celsius.

`""^"o""C"="K-273.15"`

`""^"o""C"=313 "K"-273.15=40""^"o""C"` (rounded to a whole number)